Warp letoff device



1945 A. MOESSINGER WARP LET-OFF DEVICE Filed June 3, 1943 2 Sheets-Sheetl ATTORNEY Patented May 8,. 1945 WARP LETOFF DEVICE Albert Moessinger,Winterthur, Switzerland, as-

signor to Sulzer Freres, Societe. Anonyme,

Winterthur, Switzerland 1 Application June 3, 1943, Serial No. 489,529 JIn Switzerland July 11, 1942 Claims.

Warp let-oft devices are known in which the warp beam is rotated more orless quickly by the loom, according'to the position of a tensioningdevice. In these warp let-off devices the engaging force of the couplingfitted between the loom and the warp beam acts on the tensioning deviceof the warp. The reaction of this engaging force on the tensioningdevice changes the Warp tension.

The invention eliminates this drawback and relates to a warp let-oifdevice in which the forward movement of the warp is effected by the.

loom by means of a coupling, especially a friction coupling, and thetension of the warp is kept uniform by means of a tensioning device. Theinvention consists in that there is provided, in addition to the axialrelative movement of the two coupling parts, which is determined by theposition of the tensioning device, also an axial movement, which iscaused by a device driven by the loom.

The axial movement, which is produced by a cam driven by the loom, mayact on the coupling part moving in accordance with the position of thetensioning device. This motion may also act on the coupling part whichis not moving in ac cordance with the position of the tensioning device.The two coupling parts may be pressed together by means of one or morespring parts. The spring parts, by means of which the two coupling partsare pressed together, may exert a slight pressing force which is greaterthan the force causing the forward movement of the warp.

The engaging force of the coupling applied by the tensioning device maybe released during the time when the tensioning device tensions the warpfor the next beating up. This tensioning device, during the time whenthe engaging force acts on it, can by means of a clamping device be heldstationary in the position in which it momentarily is. The position ofthe driven part of the coupling can be adjusted by the position of thetension beam; the driving part of the coupling may execute an axialreciprocating movement in addition to its rotary motions.

Fig. 1 is a diagrammatic illustration of a device according to theinvention.

Fig. 2 diagrammatically shows a modified mechanism according to theinvention.

Fig. 3 shows a detail of the mechanism accord ing to Fig. 2.

Fig. 4 diagrammatically shows a modification of the detail illustratedin Fig. 3.

Fig. 5 is a time-space diagram of the motions of the controlled parts ofthe coupling.

Referring to Fig.1 of the drawings, warp 2 running off warp beam 1 isled round a guide beam 3 and a tension beam 4, and then guided throughdividing rods 4' and separated by harness 5, after which it passes intofabric 1. The forward movement of the warp 2, or the rotation of thewarp beam I is effected by means of a worm wheel 45 and worm '44 andcoupling part 12 which is keyed to shaft 19 and can be displacedaxially. The coupling part 12 is actuated by coupling part 82, which isrotated at a constant speed by the loom through -shaft I5 by means ofshaft 83 and bevel wheels 8h The warp tension beam 4 is rotatablysupported in tension beam lever 65, which is itself carried in fixedfulcrum 61 and receives a turning moment through spring 26, this momentacting counterclockwise. To-an extension 69 of the tension beam lever 66a regulating rod II is connected by means of a spring 10. This rod II isconnected to the coupling part 12 through a toggle 13, I4 and a lever15. The toggle l3, l4

is connected to lever 11 by a link 16 and is extended or contracted intime with the loom by means of cam 18 which is driven by the loom.

When the toggle I3, 14 is in its extended position (shown in fulllines), the coupling part 12 is pressed against the coupling part 82through the force of the spring I0. Any movement of the tension beamlever 66 will now change the tension of the spring 10 and thereforecorrespondingly modify the frictional force of the coupling. If thetoggle 13, 14 is in its contracted position (shown in dotted lines), thecouplingparts 12, 82 are pulled away from each other. The regu latingrod H moves to the left under the influence of the spring 10, until thespring'lll is without tension. In that position the spring 10. ceases toact on the tension beam lever 66, so that the tension of the warp 2 iscontrolled only by thetension spring 26. The motion of the lever 11which brings the toggle I3, 14 into the extended or contracted positionby means of the cam 18, is, adjusted in such a way that the toggle l3,14 is in its contracted position each time before a weft thread isbeaten up. In this way the tension of the thread at each heating up of aweft thread is always kept constant.

In the arrangement according to Fig. 2 warp beam I supplies warp 2',which runs over guide beam 3' and tension beam 4" through the harness 5'and reed 6 to form fabric 1'. Between the reed 6 and the fabric 1' theweft thread 50 is inserted. The fabric 1' is led round a breast beam- 8,carried forward by operating roll 9, led

over guide roll lo and finally wound on to piece beam I. c

On the main shaft H of the loom a helical toothed wheel I! is keyedwhich meshes with helical toothed wheel H on shaft i5; Among the partskeyed on the shaft I5 is a bevel wheel I which meshes with bevel wheelI! revolving freely on shaft l8. On the bevel wheel II a claw whichlatter'is connected to tension spring The end of the otherarm 25 isfirmly held between two clamping plates 28 (Fig. 3), which are pressedtogether by springs 29. Rollers 30 are provided at the ends of plates 28and can be pressed apart by a key 3| connected to a free end of lever32, thus freeing the tension beam lever 23, i. e. loosening it from theclamping plates. The lever 32 is operated, for instancethrough a curvedpath 33', by a cam 33 rotated by the shaft l5.

On a fixed fulcrum 34 a lever 35 is mounted, which carries an operating,pin 36 meshing with an annular groove on the coupling part 2| The otherend of the lever 35 is connected to the tension beam lever 23 throughrod 38 and spring 39. The coupling part 2|l,has also an annular groove4|! in which rests the pin of an eccentric 4| driven by the'shaft |5.The shaft I8 is supported in two bearings 42 and 43 and carries a worm44' which engages with worm wheel 45' connected to the warp beam Y Y Thedevice operates as follows:

Upon rotation of the main shaft l2 or of the shaft l5, the eccentric 4|imparts an axial reciprocating motion to the coupling part 20.: Throughthe uniform rotation of the coupling IS, a uniform rotary motion is alsoimparted t this coupling part 20.- Depending on'the position of thetension beam 4" or of the tension lever 23, the other coupling part-2|is held back to a. greater or less extent from the coupling part 20. Thea distance between the two coupling parts 20 and 2| is designated byletter h.

In Fig. 5a time-stroke diagram of the motion of the coupling parts 2|and 22 is given. The full line 2||'- corresponds to the axial movementof the coupling part 20,'the dotted line 2| to the motion or theposition of the coupling part 2|. The distance 72 between the twocoupling parts 20 and 2| is also indicated. Through its axial movementthe coupling part 20 is pressed onto the coupling part-2l so that thelever 35 is also moved and the spring 39 is compressed. During the time1., when the two couplings 2| and 22ers pressed together, the couplingpart 2| will make the same rotary movement as the coupling 20 whichrotates at a uniform rate. 1

The smaller the distance it, the longer will be the time if during whichthe coupling 2| is rotated, and the greater will be the angular rotationof this coupling or the forward rotation of the warp beam If the warpbeam I has been turned somewhat too far, the warp 2 becomes somewhatslacker and longer and the tension beam 4" is moved to the left. Throughthis movement to the left, the

asrasie a coupling part 2| is also moved to the left, so that thedistance h increases, or the angle through which the coupling part 2| isturned is diminished. In this way the forward motion of the warp beam issomewhat slowed down until the warp 2 is again shortened and the tensionbeam 4" returns to its normal position.

Preferably the tension beam lever 23 is kept stationary by the clampingplates'28 on the arm 25 during the beating up of the weft thread 20 intothe fabric I. In accordance with the invention, during the time when thetension beam is kept stationary, the coupling part 20 is pressed againstthe coupling part 2|. Qonsequently the reaction exerted by the adjustingforce of the coupling 2| on the tension of the warp 2 is eliminated.

Fig. 4 shows a modified mechanism for temporarily fixing'the position ofthe tension beam lever 23. In this case, the tension beam lever 23 has,in addition to the arm 24', also two further arms 5| which areindividually connected to pistons 53 by piston rods 52. These pistonsoperate in two cylinders 54, which are connected by means of a centralpassage 55. In the connecting passage 55, a valve56 is arranged throughwhich the passage 55 can be closed or opened. The valve 5515 moved up ordown by means of a lever 53 pivoted at the fixed fulcrum 51.

In accordance with the invention the lever 53 or the valve 56 iscontrolled in such a way that during the time in which the two couplings20 and 2| are pressed together, the connecting passage 55 is closed. Thecylinders 54, filled with a liquid, for instance oil, will exert such agreat resistance to the motion of the pistons 53, that the tension beam4" cannot move and the reaction of the spring 39 on the tension of thewarp remains ineffective. I

The position of the tension beam 4-" is not always the same. Regulationof the movement of the warp is only possible bymodifying it. By changingthe position of the tension beam 4", a change is caused in thecontrolling force which consequently-changes the tension of the warp.

be extended as desired over for instance 10 or 20 picks. The controllingforce will also influence the tension of the warp periodically. Thisperiodic change in the warp thread tension makes itself apparent indelicate fabrics such as silk.

By means of the execution according to this invention, this alterationin the warp thread tension is eliminated, so that very delicate fabricscan be woven without any defects appearing in them.

I claim:

1. In a'loom for weaving including a substantially continuous source ofpower,- a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and with said source of power and comprisingcoupling means, warp tension means, a member connected with said tensionmeans and being responsive to changes in the tension of the warp,coupling actuating means connected with said coupling means and withsaid member, and control means connected with and driven by said sourceof power and connected with said actuating means and periodically makingthe connection between said member and said actuating means inefiective.

2. In a loom for weaving including a substantially continuous source ofpower, a warp let-oil mechanism comprising a warp beam, drive meansconnected with said beam and with said source of power and comprisingcoupling means, warp tension means, coupling actuating means connectedwith said coupling means and being connected with and responsive to saidtension means, and other, periodically acting, coupling actuating meansconnected with and driven by said source of power and connected with andperiodically actuating said coupling means in addition to said firstmentioned actuating means.

3. In a loom for weaving including a substantially continuous source ofpower, a warp let-oil mechanism comprising a warp beam, drive meansconnected with said beam and said source and comprising two shaftmembers and a friction clutch for temporarily interconnecting said twoshaft members, warp tensioning means, clutch actuating means connectedwith said clutch and also with and being responsive to said tensioningmeans, a cam mechanism connected with and continuously operated by thatsource, and control means connected with said cam mechanism and with andcontrolling the operation of said actuating means.

4. In a loom for weaving including a substantially continuous source ofpower, a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and said source and comprising a frictionclutch having two axially movable clutch members, warp tensioning means.clutch actuating means connected with one of said clutch members andalso with and being responsive to said tensioning means, an eccentricmechanism connected with and continuously operated by said source andconnected with and controlling the operation of the other of said clutchmembers. I

5. A warp let-off mechanism as set forth in claim 1 comprising resilientmeans interposed between said member and said tension means.

6. In a loom for weaving including a substantially continuous source ofpower, a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and said source and comprising clutch means,warp tensioning means, clutch actuating means connected with said clutchmeans and with and being responsive to said tensioning means, andcontrol means connected with and operated by said source andperiodically interrupting the action of said tensioning means on saidactuating means.

'7. In a loom for weaving including a substantially continuous source ofpower, a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and said source and comprising clutch means,warp tensioning means, clutch actuating means connected with said clutchmeans and with and being responsive to said tensioning means, andcontrol means connected with an operated by said source and connectedwith said actuating means and periodically interrupting the influence ofsaid tensioning means on said actuating means.

8. In a loom for weaving includin a substantially continuous source ofpower, a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and said source and comprising clutch means,warp tensioning means, clutch actuating means connected with said clutchmeans and with and being responsive to said tensioning means, andcontrol means connected with and operated by said source and connectedwith said tensioning means and periodically interrupting the influenceof said tensioning means on said actuating means.

9. In a loom for weaving including a substantially continuous source ofpower, a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and said source and comprising clutch means,warp tensioning means, clutch actuatin means connected with said clutchmeans and with and being responsive to said tensioning means, andarresting means connected with and operated by said source andperiodically arresting said tensioning means at the position in whichthey are at the moment of arresting.

10. In a loom for weaving including a substantially continuous source ofpower, a warp let-off mechanism comprising a warp beam, drive meansconnected with said beam and with said source of power and comprisingcoupling means, warp tension means, spring means connected with saidtension means and coupling actuating means connected with said springmeans and with said coupling means and being resiliently responsive tosaid tension means.

ALBERT MOESSINGER.

